mirror of
https://github.com/Atmosphere-NX/Atmosphere.git
synced 2024-12-27 12:46:03 +00:00
246 lines
7.9 KiB
C
246 lines
7.9 KiB
C
|
// Tencent is pleased to support the open source community by making RapidJSON available.
|
||
|
|
//
|
||
|
|
// Copyright (C) 2015 THL A29 Limited, a Tencent company, and Milo Yip.
|
||
|
|
//
|
||
|
|
// Licensed under the MIT License (the "License"); you may not use this file except
|
||
|
|
// in compliance with the License. You may obtain a copy of the License at
|
||
|
|
//
|
||
|
|
// http://opensource.org/licenses/MIT
|
||
|
|
//
|
||
|
|
// Unless required by applicable law or agreed to in writing, software distributed
|
||
|
|
// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
|
||
|
|
// CONDITIONS OF ANY KIND, either express or implied. See the License for the
|
||
|
|
// specific language governing permissions and limitations under the License.
|
||
|
|
|
||
|
|
// This is a C++ header-only implementation of Grisu2 algorithm from the publication:
|
||
|
|
// Loitsch, Florian. "Printing floating-point numbers quickly and accurately with
|
||
|
|
// integers." ACM Sigplan Notices 45.6 (2010): 233-243.
|
||
|
|
|
||
|
|
#ifndef RAPIDJSON_DTOA_
|
||
|
|
#define RAPIDJSON_DTOA_
|
||
|
|
|
||
|
|
#include "itoa.h" // GetDigitsLut()
|
||
|
|
#include "diyfp.h"
|
||
|
|
#include "ieee754.h"
|
||
|
|
|
||
|
|
RAPIDJSON_NAMESPACE_BEGIN
|
||
|
|
namespace internal {
|
||
|
|
|
||
|
|
#ifdef __GNUC__
|
||
|
|
RAPIDJSON_DIAG_PUSH
|
||
|
|
RAPIDJSON_DIAG_OFF(effc++)
|
||
|
|
RAPIDJSON_DIAG_OFF(array-bounds) // some gcc versions generate wrong warnings https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59124
|
||
|
|
#endif
|
||
|
|
|
||
|
|
inline void GrisuRound(char* buffer, int len, uint64_t delta, uint64_t rest, uint64_t ten_kappa, uint64_t wp_w) {
|
||
|
|
while (rest < wp_w && delta - rest >= ten_kappa &&
|
||
|
|
(rest + ten_kappa < wp_w || /// closer
|
||
|
|
wp_w - rest > rest + ten_kappa - wp_w)) {
|
||
|
|
buffer[len - 1]--;
|
||
|
|
rest += ten_kappa;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
inline int CountDecimalDigit32(uint32_t n) {
|
||
|
|
// Simple pure C++ implementation was faster than __builtin_clz version in this situation.
|
||
|
|
if (n < 10) return 1;
|
||
|
|
if (n < 100) return 2;
|
||
|
|
if (n < 1000) return 3;
|
||
|
|
if (n < 10000) return 4;
|
||
|
|
if (n < 100000) return 5;
|
||
|
|
if (n < 1000000) return 6;
|
||
|
|
if (n < 10000000) return 7;
|
||
|
|
if (n < 100000000) return 8;
|
||
|
|
// Will not reach 10 digits in DigitGen()
|
||
|
|
//if (n < 1000000000) return 9;
|
||
|
|
//return 10;
|
||
|
|
return 9;
|
||
|
|
}
|
||
|
|
|
||
|
|
inline void DigitGen(const DiyFp& W, const DiyFp& Mp, uint64_t delta, char* buffer, int* len, int* K) {
|
||
|
|
static const uint32_t kPow10[] = { 1, 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000, 1000000000 };
|
||
|
|
const DiyFp one(uint64_t(1) << -Mp.e, Mp.e);
|
||
|
|
const DiyFp wp_w = Mp - W;
|
||
|
|
uint32_t p1 = static_cast<uint32_t>(Mp.f >> -one.e);
|
||
|
|
uint64_t p2 = Mp.f & (one.f - 1);
|
||
|
|
int kappa = CountDecimalDigit32(p1); // kappa in [0, 9]
|
||
|
|
*len = 0;
|
||
|
|
|
||
|
|
while (kappa > 0) {
|
||
|
|
uint32_t d = 0;
|
||
|
|
switch (kappa) {
|
||
|
|
case 9: d = p1 / 100000000; p1 %= 100000000; break;
|
||
|
|
case 8: d = p1 / 10000000; p1 %= 10000000; break;
|
||
|
|
case 7: d = p1 / 1000000; p1 %= 1000000; break;
|
||
|
|
case 6: d = p1 / 100000; p1 %= 100000; break;
|
||
|
|
case 5: d = p1 / 10000; p1 %= 10000; break;
|
||
|
|
case 4: d = p1 / 1000; p1 %= 1000; break;
|
||
|
|
case 3: d = p1 / 100; p1 %= 100; break;
|
||
|
|
case 2: d = p1 / 10; p1 %= 10; break;
|
||
|
|
case 1: d = p1; p1 = 0; break;
|
||
|
|
default:;
|
||
|
|
}
|
||
|
|
if (d || *len)
|
||
|
|
buffer[(*len)++] = static_cast<char>('0' + static_cast<char>(d));
|
||
|
|
kappa--;
|
||
|
|
uint64_t tmp = (static_cast<uint64_t>(p1) << -one.e) + p2;
|
||
|
|
if (tmp <= delta) {
|
||
|
|
*K += kappa;
|
||
|
|
GrisuRound(buffer, *len, delta, tmp, static_cast<uint64_t>(kPow10[kappa]) << -one.e, wp_w.f);
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// kappa = 0
|
||
|
|
for (;;) {
|
||
|
|
p2 *= 10;
|
||
|
|
delta *= 10;
|
||
|
|
char d = static_cast<char>(p2 >> -one.e);
|
||
|
|
if (d || *len)
|
||
|
|
buffer[(*len)++] = static_cast<char>('0' + d);
|
||
|
|
p2 &= one.f - 1;
|
||
|
|
kappa--;
|
||
|
|
if (p2 < delta) {
|
||
|
|
*K += kappa;
|
||
|
|
int index = -kappa;
|
||
|
|
GrisuRound(buffer, *len, delta, p2, one.f, wp_w.f * (index < 9 ? kPow10[index] : 0));
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
inline void Grisu2(double value, char* buffer, int* length, int* K) {
|
||
|
|
const DiyFp v(value);
|
||
|
|
DiyFp w_m, w_p;
|
||
|
|
v.NormalizedBoundaries(&w_m, &w_p);
|
||
|
|
|
||
|
|
const DiyFp c_mk = GetCachedPower(w_p.e, K);
|
||
|
|
const DiyFp W = v.Normalize() * c_mk;
|
||
|
|
DiyFp Wp = w_p * c_mk;
|
||
|
|
DiyFp Wm = w_m * c_mk;
|
||
|
|
Wm.f++;
|
||
|
|
Wp.f--;
|
||
|
|
DigitGen(W, Wp, Wp.f - Wm.f, buffer, length, K);
|
||
|
|
}
|
||
|
|
|
||
|
|
inline char* WriteExponent(int K, char* buffer) {
|
||
|
|
if (K < 0) {
|
||
|
|
*buffer++ = '-';
|
||
|
|
K = -K;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (K >= 100) {
|
||
|
|
*buffer++ = static_cast<char>('0' + static_cast<char>(K / 100));
|
||
|
|
K %= 100;
|
||
|
|
const char* d = GetDigitsLut() + K * 2;
|
||
|
|
*buffer++ = d[0];
|
||
|
|
*buffer++ = d[1];
|
||
|
|
}
|
||
|
|
else if (K >= 10) {
|
||
|
|
const char* d = GetDigitsLut() + K * 2;
|
||
|
|
*buffer++ = d[0];
|
||
|
|
*buffer++ = d[1];
|
||
|
|
}
|
||
|
|
else
|
||
|
|
*buffer++ = static_cast<char>('0' + static_cast<char>(K));
|
||
|
|
|
||
|
|
return buffer;
|
||
|
|
}
|
||
|
|
|
||
|
|
inline char* Prettify(char* buffer, int length, int k, int maxDecimalPlaces) {
|
||
|
|
const int kk = length + k; // 10^(kk-1) <= v < 10^kk
|
||
|
|
|
||
|
|
if (0 <= k && kk <= 21) {
|
||
|
|
// 1234e7 -> 12340000000
|
||
|
|
for (int i = length; i < kk; i++)
|
||
|
|
buffer[i] = '0';
|
||
|
|
buffer[kk] = '.';
|
||
|
|
buffer[kk + 1] = '0';
|
||
|
|
return &buffer[kk + 2];
|
||
|
|
}
|
||
|
|
else if (0 < kk && kk <= 21) {
|
||
|
|
// 1234e-2 -> 12.34
|
||
|
|
std::memmove(&buffer[kk + 1], &buffer[kk], static_cast<size_t>(length - kk));
|
||
|
|
buffer[kk] = '.';
|
||
|
|
if (0 > k + maxDecimalPlaces) {
|
||
|
|
// When maxDecimalPlaces = 2, 1.2345 -> 1.23, 1.102 -> 1.1
|
||
|
|
// Remove extra trailing zeros (at least one) after truncation.
|
||
|
|
for (int i = kk + maxDecimalPlaces; i > kk + 1; i--)
|
||
|
|
if (buffer[i] != '0')
|
||
|
|
return &buffer[i + 1];
|
||
|
|
return &buffer[kk + 2]; // Reserve one zero
|
||
|
|
}
|
||
|
|
else
|
||
|
|
return &buffer[length + 1];
|
||
|
|
}
|
||
|
|
else if (-6 < kk && kk <= 0) {
|
||
|
|
// 1234e-6 -> 0.001234
|
||
|
|
const int offset = 2 - kk;
|
||
|
|
std::memmove(&buffer[offset], &buffer[0], static_cast<size_t>(length));
|
||
|
|
buffer[0] = '0';
|
||
|
|
buffer[1] = '.';
|
||
|
|
for (int i = 2; i < offset; i++)
|
||
|
|
buffer[i] = '0';
|
||
|
|
if (length - kk > maxDecimalPlaces) {
|
||
|
|
// When maxDecimalPlaces = 2, 0.123 -> 0.12, 0.102 -> 0.1
|
||
|
|
// Remove extra trailing zeros (at least one) after truncation.
|
||
|
|
for (int i = maxDecimalPlaces + 1; i > 2; i--)
|
||
|
|
if (buffer[i] != '0')
|
||
|
|
return &buffer[i + 1];
|
||
|
|
return &buffer[3]; // Reserve one zero
|
||
|
|
}
|
||
|
|
else
|
||
|
|
return &buffer[length + offset];
|
||
|
|
}
|
||
|
|
else if (kk < -maxDecimalPlaces) {
|
||
|
|
// Truncate to zero
|
||
|
|
buffer[0] = '0';
|
||
|
|
buffer[1] = '.';
|
||
|
|
buffer[2] = '0';
|
||
|
|
return &buffer[3];
|
||
|
|
}
|
||
|
|
else if (length == 1) {
|
||
|
|
// 1e30
|
||
|
|
buffer[1] = 'e';
|
||
|
|
return WriteExponent(kk - 1, &buffer[2]);
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
// 1234e30 -> 1.234e33
|
||
|
|
std::memmove(&buffer[2], &buffer[1], static_cast<size_t>(length - 1));
|
||
|
|
buffer[1] = '.';
|
||
|
|
buffer[length + 1] = 'e';
|
||
|
|
return WriteExponent(kk - 1, &buffer[0 + length + 2]);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
inline char* dtoa(double value, char* buffer, int maxDecimalPlaces = 324) {
|
||
|
|
RAPIDJSON_ASSERT(maxDecimalPlaces >= 1);
|
||
|
|
Double d(value);
|
||
|
|
if (d.IsZero()) {
|
||
|
|
if (d.Sign())
|
||
|
|
*buffer++ = '-'; // -0.0, Issue #289
|
||
|
|
buffer[0] = '0';
|
||
|
|
buffer[1] = '.';
|
||
|
|
buffer[2] = '0';
|
||
|
|
return &buffer[3];
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
if (value < 0) {
|
||
|
|
*buffer++ = '-';
|
||
|
|
value = -value;
|
||
|
|
}
|
||
|
|
int length, K;
|
||
|
|
Grisu2(value, buffer, &length, &K);
|
||
|
|
return Prettify(buffer, length, K, maxDecimalPlaces);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
#ifdef __GNUC__
|
||
|
|
RAPIDJSON_DIAG_POP
|
||
|
|
#endif
|
||
|
|
|
||
|
|
} // namespace internal
|
||
|
|
RAPIDJSON_NAMESPACE_END
|
||
|
|
|
||
|
|
#endif // RAPIDJSON_DTOA_
|